diff --git a/test/maths.cpp b/test/maths.cpp
index 4882b43e..7c954d0e 100644
--- a/test/maths.cpp
+++ b/test/maths.cpp
@@ -3,15 +3,23 @@
 
 #include <cstdlib>
 #include <cmath>
-
+#include <limits>
 
 using std::sqrt;
-
+using std::numeric_limits;
 
 int
 main (int, char **) {
     check_hard (!almost_equal (-2.0, 0.0));
     check_hard (!almost_equal (-2.f, 0.f));
+    check_hard ( almost_equal ( 0.0, 0.0));
+    check_hard ( almost_equal ( 0.0, numeric_limits<double>::min ()));
+    check_hard ( almost_equal (numeric_limits<double>::infinity (),
+                               numeric_limits<double>::infinity ()));
+    check_hard (!almost_equal (numeric_limits<double>::infinity (), 0.0));
+    check_hard (!almost_equal (numeric_limits<double>::quiet_NaN (),
+                               numeric_limits<double>::quiet_NaN ()));
+
 
     check_eq (min (-2, 0, 2), -2);
     check_eq (max (-2, 0, 2),  2);
@@ -21,5 +29,18 @@ main (int, char **) {
 
     check_eq (rootsquare (2, 2), sqrt (8));
 
+    double pos_zero =  1.0 / numeric_limits<double>::infinity ();
+    double neg_zero = -1.0 / numeric_limits<double>::infinity ();
+
+    check_eq (sign (-1),   -1);
+    check_eq (sign ( 1),    1);
+    check_eq (sign (pos_zero),  1);
+    check_eq (sign (neg_zero), -1);
+    check_eq (sign ( numeric_limits<double>::infinity ()),  1);
+    check_eq (sign (-numeric_limits<double>::infinity ()), -1);
+
+    check_eq (to_degrees (PI),  180);
+    check_eq (to_radians (180),  PI);
+
     return EXIT_SUCCESS;
 }